Hand-setting mechanism for back winding watch

ABSTRACT

A hand-setting mechanism for a watch having a winding stem axially displaceable freely to a hand-setting position. The winding stem is used for winding the watch in its normal winding position and is displaceable axially by a crown thereon for coupling a transmission gear driven by the winding stem to a hand-setting gear of a hand-setting gear train for setting the hands of a watch. Semi-automatic means in the form of a spring biasing one of the two gears to be coupled by axial movement under control of the spring is enabled when the winding stem is displaced to its hand-setting position and disenabled when it is returned to its normal winding position.

United States Patent [1 1 [111 3,879,933 Ikehata 1 1 Apr. 29, 1975 [5HAND-SETTING MECHANISM FOR BACK 3.499.280 3/1970 Erard 58/63 WINDINGWATCH 3.555.919 1/1971 Odell 74/355 Primary Emminer-George H. Miller,Jr. Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato: BruceL, Adams [57] ABSTRACT A hand-setting mechanism for a watch having awinding stem axially displaceable freely to a hand-setting position. Thewinding stem is used for winding the watch in its normal windingposition and is displaceable axially by a crown thereon for coupling atransmission gear driven by the winding stem to a handsetting gear of ahand-setting gear train for setting the hands of a watch. Semi-automaticmeans in the form of a spring biasing one of the two gears to be coupledby axial movement under control of the spring is enabled when thewinding stem is displaced to its handsetting position and disenabledwhen it is returned to its normal winding position.

3 Claims, 2 Drawing Figures 1 C .\\\\\\\\\\\\\\I!?. I g ll/////HAND-SETTING MECHANISM FOR BACK WINDING WATCH BACKGROUND OF THEINVENTION This invention relates generally to watches and moreparticularly to back winding watches and a handsetting mechanismtherefore.

Generally in back winding watches a hand-setting operation is effectedby a transmission gear mounted on the end of a hand-setting stem whichmeshes with a setting gear or an intermediate gear which drives theminute gear when the winding crown on the stem is pulled up. These knownwatches have several problems in that the transmission gear fails tomesh with the handsetting gear or intermediate setting gear when theteeth of the two gears are out of phase in respect to meshing with eachother. The transmission gear is generally fixedly mounted on the windingstern and the handsetting gear or intermediate setting gear to becoupled to the transmission gear is not axially displaceable orslidable. Therefore if the gears are out of phase for meshing of the twogears when the winding stem is pulled upwardly it can only be displacedto a halfway position. Since the winding stem cannot be pulled out toits full position sometimes the wearer of the watch will attempt toforcibly pull out the winding stem from the winding position to thehand-setting position and this will result in breaking one of the twogears or the winding stem or crown thereon.

Another problem is that in setting the hands of the watch if the gearswill not mesh when the winding stem is first pulled out the crown has tobe first rotated to place the gears of the teeth of the two gears inproper phase so that the coupling can take place and then pulledoutwardly. This results in the inconvenience of having to adjust thewinding stem twice to adjust the gears.

SUMMARY OF THE INVENTION It is a principal object of the presentinvention to provide a novel hand-setting mechanism for a back windingwatch in which the mechanism is automatically enabled by the movement ofthe winding stern even though the gears coupling the winding mechanismand winding step are out of phase for meshing or being coupled.

Another object of the present invention is to provide a hand-settingmechanism in which the winding stem is axially movable to two operativepositions without restriction even if gears to be coupled thereby areout of phase for being coupled.

According to the present invention a watch is provided with ahand-setting mechanism comprising the winding stern of the watch whichis axially displaceable from a winding first position to a hand-settingsecond position. The winding stem is activated by a crown for axiallydisplacing it and rotating it. A transmission gear is rotatably drivenby the winding stem and a handsetting gear train has a hand-setting geartherein coupleable to the transmission gear. Semi-automatic meansenabled by the winding stem to couple the transmission gear andhand-setting gear are provided. This semi-automatic means is enabled tocouple the transmission gear and the hand-setting gear even when theteeth of the transmission gear and hand-setting gear are out of phasefor meshing.

Provision is made in the semi-automatic means of the hand-settingmechanism of the invention for mounting either the transmission geardriven by the winding stem or the hand-setting gear to be axiallydisplaceable thereby allowing the full axial relative movement ofthewinding stem each time it is moved to the hand-setting position and inthe event that there is interference between the gears. Spring meansprovided bias one of the two gears that are to be coupled intoengagement once the gear teeth thereof are in phase for meshing orcoupling.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of thehand-setting mechanism for a watch according to the invention willappear from the following description of an example of the invention,and the novel features will be particularly pointed out in the appendedclaims and drawing in which:

FIG. I is a fragmentary cross section view of a watch embodying ahand-setting mechanism according to the invention; and

FIG. 2 is a second embodiment ofa watch embodying a hand-settingmechanism according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS The drawings illustrate twoembodiments of a back winding watch each provided with a hand-settingmechanism according to the invention. As illustrated in FIG. I, arotatable winding stem I is slidable axially in opposite directions andcarries a winding crown 2 at its outer end which is outside of a watchcasing member 3, for example a back cover. Inside of the casing thewinding stem passes axially through openings in a barrel bridge 4 andplate 5. An inner portion of the winding stem is provided with a squarestem portion lb through an interconnecting intermediate step portion la.

A transmission gear 6 is slidably mounted for axial movement on thewinding stem square portion lb that is rotatable with the winding stemwhen it is rotatably driven. A spring 7 disposed under the inner orlower surface of the transmission gear 6 urges the transmission gear onthe stem in a direction toward the crown of the winding stern so thatthe transmission gear resiliently abuts on the step portion la of thewinding stern. An intermediate hand-setting gear 8 of a hand-settinggear train is rotatably mounted between the plate 5 and a setting leverspring 9 so as to mesh with the transmission gear whenever the windingstem 1 is pulled out for setting the hands of the watch.

A hand-setting gear 10 of a hand-setting gear train meshes with theintermediate or hand-setting gear 8 and likewise meshes with a minutegear 11. The winding stem has thereon a winding gear 12 rotational onthe winding stem for winding a ratchet gear wheel 13 that meshestherewith. The winding gear 12 has ratchet teeth which mesh with aclutch gear 14 which rotates with the stern when the winding crown isrotated in the winding position illustrated in the drawing. This clutchis biased toward engagement and disengages or declutches from thewinding gear 12 when the winding crown 2 is pulled upwardly from itswinding or first position to a hand-setting or second position. A collaron the winding stem moves it upwardly.

In the position illustrated in the drawing the winding crown 2 is notpulled outwardly and the winding stem from so that the teeth thereof'aredisplaced axially' downwardly from the gear teeth of the intermediatehand-setting gear 8. Therefore. it is not possible to set the hands ofthe watch in this state.

in order to set the hands the winding crown 2 is pulledoutwardly fromthe first position shown to a second or hand-setting position. Thewinding stem moves axially upwards as shown in the drawing or outwardlyof the watch and at the same time the transmission gear 6 is biasedaxially of the stem by the spring 7. As a resultthe peripheral teeth ofthe transmission gear 6 are moved into engagement with the peripheralteeth of the intermediate gear 8 and both mesh smoothly with each otherwithout hinderance once the gears are in the proper phase for meshing.

It will be noted that the winding stem 1 can be completely moved to itssecond axial position in spite of the transmission gear 6 being stoppedin its axial travel at a time when it strikes against the intermediategear 8 if the respective gear teeth of both gears are out of phase formeshing at the time since the transmission gear 6 is axially slidable onthe winding stem.

Once the winding stem is in its hand-setting or second position thewinding crown 2 can be rotated and the transmission gear 6 rotatestogether with the winding stem because it has an opening which is squarein configuration into which the square portion lb of the winding stemfits. As the crown 2 is rotated the transmission gear 6 is properlylined-up with the intermediate gear 8 and the transmission gear is movedautomatically into engagement with the hand-setting or intermediate gear8 by the action of the spring 7 at a point where the teeth are in theproper phase for meshing. Whereby the cou pling is automaticallyrendered effective by the winding stem.

A second embodiment of a watch embodying a handsetting mechanismaccording to the invention as illustrated in FIG. 1. In this embodimentthe parts corresponding to those of FIG. 1 have corresponding referencenumerals which are primed. Thus, a winding stem 1 is mounted in a watchextending thereto through a barrel bridge 4' and has a transmission gear6' fixed thereto so that this gear is unable to slide axially relativethe winding stem. An intermediate hand-setting wheel 8' is pivotlymounted, between the barrel bridge 4' and setting lever spring 9', on anaxle 15. A spring 7' is disposed in a space defined between theintermediate hand-setting gear 8' and the axle 15. The upper end of thespring 7 abuts on a shoulder a of the axle 15 while its lower end abutson a washer 8'c of the intermediate hand-setting gear 8 provided with aset of lower peripheral teeth 8'b so that the lower surface of theintermediate hand-setting gear 8' is urged to resiliently abut againststop 16 which is mounted on the axle 15. The intermediate hand-setting8' is provided with upper peripheral teeth 8a. The lower teeth 8'b ofthe intermediate hand-setting gear 8 ordinarily mesh with thehand-setting gear 10' which meshes with a minute gear 11'. The stop 16insures that the engagement position of the transmission gear with theupper teeth 8'a of the intermediate hand setting gear 8' takes place.

Consequently in this second embodiment when the wearer of the watchpulls the winding crown outwardly from its winding or first position toits second axial position for setting the watch hands, not shown, thetransmission gear 6' moves together with the winding stem 1' andengagesor meshes with the upper teeth 8a of the intermediatehand-setting gear 8 in case that the corresponding teeth of both wheelsare in phase similarly to the embodiment in FIG. I.

If the respective teeth of the two gears that are to be coupled are outof phase for meshing the intermediate hand-setting gear 8' is liftedagainst the action of the spring 7 since it is slidable axially ontheaxle 15. As a result the winding stem 1 can be moved freely from itsfirst position shown in the drawing to its second or hand-settingposition. By rotating the winding crown on the winding stem'to set thehands the intermediate hand-settinglgear 8, which is usually biaseddownwardly by thespring 7' moves axially to a position against the stop16, is automatically coupled to the transmission gear whereby thehand-setting may be effected.

Those skilled in the art will recognize that the back winding watchprovided with the hand-setting mechanism of the invention is providedwith semi-automatic means for engaging the intermediate hand-settinggear with the transmission gear after the winding stem has been movedupwardly even if the teeth of the two gears are out of phase for meshingwhen the winding crown is pulled out to set the hands. This isaccomplished since either the transmission gear or the intermediatehand-setting gear are relatively axially slidable relative to acorresponding pivot shaft and are biased for automatic coupling by meansof spring which urges either one of them to engage with the other gear.Therefore the inconveniences and drawbacks of the prior art mentionedabove are entirely eliminated.

What I claim and desire to secure by letters patent is:

1. In a watch, a hand-setting mechanism comprising a winding stemaxially displaceable freely from a winding first position to ahand-setting second position, a crown on said winding stern for axiallydisplacing said winding stem and for rotating it, a transmission gearrotatably driven by said winding stem, a hand-setting gear train havinga hand-setting gear coupleable to the transmission gear, semi-automaticmeans enabled by said winding stem when displaced to said secondposition thereof to couple said transmission gear and said hand-settinggear when the gear teeth of said transmission gear and said hand-settinggear are in phase for meshing and for enabling said winding stem to befreely displaceable to said second position when said gear teeth are notin phase for meshing.

2. In 'a watch according to claim 1, in which said semi-automatic meanscomprises means on said winding stem mounting said transmission gear foraxial movement relative to said winding stem and for rotation therewith,and a spring biasing the transmission gear axially toward the crown onsaid stem.

3. In a watch according to claim 1, in which said transmission gear'isfixed to said winding stem for movement therewith, and in which saidsemi-automatic means comprises means mounting said hand-setting gear foraxial movement and rotation thereon, and a spring biasingthe'ha'nd-setting gear axially in a direction for meshing with saidtransmission gear.

1. In a watch, a hand-setting mechanism comprising a winding stemaxially displaceable freely from a winding first position to ahand-setting second position, a crown on said winding stem for axiallydisplacing said winding stem and for rotating it, a transmission gearrotatably driven by said winding stem, a handsetting gear train having ahand-setting gear coupleable to the transmission gear, semi-automaticmeans enabled by said winding stem when displaced to said secondposition thereof to couple said transmission gear and said hand-settinggear when the gear teeth of said transmission gear and said hand-settinggear are in phase for meshing and for enabling said winding stem to befreely displaceable to said second position when said gear teeth are notin phase for meshing.
 2. In a watch according to claim 1, in which saidsemi-automatic means comprises means on said winding stem mounting saidtransmission gear for axial movement relative to said winding stem andfor rotation therewith, and a spring biasing the transmission gearaxially toward the crown on said stem.
 3. In a watch according to claim1, in which said transmission gear is fixed to said winding stem formovement therewith, and in which said semi-automatic means comprisesmeans mounting said hand-setting gear for axial movement and rotationthereon, and a spring biasing the hand-setting gear axially in adirection for meshing with said transmission gear.